Motion of vortices implies chaos in Bohmian mechanics

Bohmian mechanics is a causal interpretation of quantum mechanics in which particles describe trajectories guided by the wave function. The dynamics in the vicinity of nodes of the wave function, usually called vortices, is regular if they are at rest. However, vortices generically move during time evolution of the system. We show that this movement is the origin of chaotic behavior of quantum trajectories. As an example, our general result is illustrated numerically in the two-dimensional isotropic harmonic oscillator.Comment: 7 pages 5 figure

Familial risks of esophageal cancer among the Turkmen population of the Caspian littoral of Iran

In northeastern Iran, there is an area of high incidence of esophageal cancer, which is populated by residents of Turkmen ancestry. Several environmental risk factors for esophageal cancer have been proposed, but the roles of familial and genetic factors have not been studied extensively in the Turkmen population. We evaluated the importance of familial risk factors for esophageal cancer by performing a case-control study of 167 cases of esophageal squamous cell carcinoma and 200 controls of Turkmen ethnicity. Detailed family pedigrees of the cases and controls were constructed, which documented all cancers in first- and second-degree relatives. The actuarial risk of cancer was then estimated in 2,097 first-degree relatives of cases and 2,783 first-degree relatives of the controls. A hazard ratio was constructed, based on a comparison of the 2 cumulative incidence curves. The risk to age 75 of esophageal cancer in the first-degree relatives of Turkmen patients with esophageal cancer was 34% versus 14% for the first-degree relatives of the controls (hazard ratio = 2.3; p = 3 × 10⁻⁸). Cases (9.6%) reported that their parents were related, versus 2.5% of the controls who reported this, (odds ratio = 4.1; p value = 0.006). Familial factors are important in the etiology of esophageal cancer among the Turkmen residents of Iran. The hazard ratio of 2.3 for cancer among first-degree relatives is consistent with an important contribution of heritable factors. It will be of interest to perform marker studies to establish which genes are responsible. © 2006 Wiley-Liss, Inc

DNA repair genes XRCC1 and XRCC3 polymorphisms and their relationship with the level of micronuclei in breast cancer patients

Breast cancer (BC) is the most prevalent type worldwide, besides being one of the most common causes of death among women. It has been suggested that sporadic BC is most likely caused by low-penetrance genes, including those involved in DNA repair mechanisms. Furthermore, the accumulation of DNA damage may contribute to breast carcinogenesis. In the present study, the relationship between two DNA repair genes, viz., XRCC1 (Arg399Gln) and XRCC3 (Thr241Met) polymorphisms, and the levels of chromosome damage detected in 65 untreated BC women and 85 healthy controls, was investigated. Chromosome damage was evaluated through micronucleus assaying, and genotypes determined by PCR-RFLP methodology. The results showed no alteration in the risk of BC and DNA damage brought about by either XRCC1 (Arg399Gln) or XRCC3 (Thr241Met) action in either of the two groups. Nevertheless, on evaluating BC risk in women presenting levels of chromosome damage above the mean, the XRCC3Thr241Met polymorphism was found to be more frequent in the BC group than in the control, thereby leading to the conclusion that there is a slight association between XRCC3 (241 C/T) genotypes and BC risk in the subgroups with higher levels of chromosome damage

Fruit and Vegetable Intake and Hip Fracture Incidence in Older Men and Women: The CHANCES Project

The role of fruit and vegetable intake in relation to fracture prevention during adulthood and beyond is not adequately understood. We investigated the potential association between fruit and vegetable intake and hip fracture incidence in a large sample of older adults from Europe and the United States. A total of 142,018 individuals (116,509 women) aged ≥60 years, from five cohorts, were followed up prospectively for 1,911,482 person-years, accumulating 5552 hip fractures. Fruit and vegetable intake was assessed by validated, cohort-specific, food-frequency questionnaires (FFQ). Ηip fractures were ascertained through national patient registers or telephone interviews/questionnaires. Adjusted hazard ratios (HRs) derived by Cox proportional hazards regression were estimated for each cohort and subsequently pooled using random effects meta-analysis. Intake of ≤1 serving/day of fruit and vegetables combined was associated with 39% higher hip fracture risk (pooled adjusted HR, 1.39; 95% confidence interval [CI], 1.20 to 1.58) in comparison with moderate intake (>3 and ≤5 servings/day) (pfor heterogeneity = 0.505), whereas higher intakes (>5 servings/day) were not associated with lower risk in comparison with the same reference. Associations were more evident among women. We concluded that a daily intake of 1 or <1 servings of fruits and vegetables was associated with increased hip fracture risk in relation to moderate daily intakes. Older adults with such low fruit and vegetable consumption may benefit from raising their intakes to moderate amounts in order to reduce their hip fracture risk. © 2016 American Society for Bone and Mineral Research. © 2016 American Society for Bone and Mineral Researc